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Discussion Starter #1
Got a sheetmetal roller at work and I'm thinking about trying to roll some megaphones for the 160. I've got the pattern geometry all worked out...seems pretty simple. About 17" long, 2 1/2" opening at the "big" end. Maybe a single baffle plate.

I'm not interested in stainless or anything too fancy. Plain ol' sheetmetal good enough?

Any other tips?

Honda go sideways!
 

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Krap,
You got a slip roller or a standard type sheet metal roller? A straight roller won't roll cone shapes. Talk to JB.

Cheers, Bret @ Glass from the Past
 

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Might be easier just to order one of mine:
http://www.jrbranson.com/BikeParts/CDR-Parts.htm

But....the whole roller thing, kinda stange. I have a "slip roll"...however, unless it's an old school, very nice, very expensive roller it won't really "slip" with any degree of realiability. Basically you want the roller to roll one end more than the other...by "more" I mean you want it to roll more metal...not more of a roll...if you take my meaning. On a small meg the small end of the meg will most likely be smaller in OD than the rollers...you want that end to "slip"..rolling only about 3 inches or so of metal...while the big end should "grab" and roll about 9" of metal. So the piece of triangular shaped metal is kind of pivoting from the small end.
In theory sounds great, but getting the cheap chinese rollers to slip with any degree of accuracy is damn near impossible. I have developed some methods to roll them pretty easy, includes some hand forming and clamping after rolling.
I also have cool software that generates the drawings for any size meg or cone. But...if you look in the Sheetmetal workers handbook you'll find formulas for making the patterns. I have about a dozen patterns of different dimensions in metal I keep on hand to just trace out on the sheet and cut.
Welding the seam can be tedious without a TIG and the proper rod.
JohnnyB

PS. Most slip rollers also have a removable top roller...so you can get the piece off after you roll it.

PSS. 17" sounds kind of short for a 160. I like about 27"...or as long as I can possibly roll for the 160/175. The longer narrower megs provide more torque....and the 160/175 need all the torque they can get.

Edited by - jbranson on Jan 31 2007 10:41:35 PM

Edited by - jbranson on Jan 31 2007 10:43:40 PM
 

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Discussion Starter #5
It's an old-ass sheet metal roller (circa 1950). Straight outta industrial arts class, if you get my drift. About 3 feet across, top roller lifts out, hand crank, adjustable roller on the backside. The adjuster is degreed on one side.

Yeah, getting the small end small enough might be a dealbreaker.

I got a million parts on order and I'm just trying to kill some time.

Race school's in June and there's about a billion things yet to do.





Honda go sideways!
 

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I've got a little 30" slip roll...1.5" OD rollers...it's borderline for making the small end of megs for the smaller bikes. Still requries lots of hose clamping and massaging to get it right after it comes out of the roller.
JohnnyB
 
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